Numerical Analysis for Design of Composite Specimens for Through-the-Thickness Tensile Measurements

Abstract

The research reported in this paper was motivated by the need for measuring through-the-thickness tensile properties of composite panels. Such measurements are especially necessary for three-dimensional textile structural composites, in which the rein-forcement effect in the thickness direction is significant. A multi-section specimen design which includes gauge section, transition section and grip section is proposed. The two-dimensional boundary element technique has been adopted for analyzing the characteristics of the stress distribution in the specimen. A general singular boundary element with arbitrary order of the stress singularity has been formulated. Verification studies show good accuracy of the analytical method. The geometric and material factors affecting the stress distribution and stress singularity have been identified. Finally, recommendations have been made for multi-section specimen design in achieving high uniformity of stress distribution within the gauge section and low intensity of the stress singularity in the interface between the gauge and transition sections.